Observed topology
AS237 MERIT-AS-14
Transit
Upstream networks
Networks observed carrying traffic for AS237: the AS immediately before it in a routing path. Ranked by how many paths showed the relationship, which reflects how widely it is used, not how much traffic crosses it.
| AS | Network | Type | Families | Paths seen |
|---|---|---|---|---|
| AS1299 | Arelion Sweden AB | Transit | IPv4 IPv6 | 1,991 |
| AS174 | Cogent Communications, LLC | Transit | IPv4 IPv6 | 956 |
| AS6939 | Hurricane Electric LLC | Transit | IPv4 IPv6 | 777 |
| AS2914 | NTT America, Inc. | Transit | IPv4 IPv6 | 689 |
| AS11537 | Internet2 | Unclassified | IPv4 IPv6 | 417 |
| AS7018 | AT&T Enterprises, LLC | Residential | IPv4 IPv6 | 222 |
| AS11164 | Internet2 | Education | IPv4 IPv6 | 94 |
| AS14907 | Wikimedia Foundation Inc. | Hosting | IPv4 IPv6 | 90 |
| AS293 | ESnet | Unclassified | IPv4 | 83 |
| AS3303 | Swisscom (Schweiz) AG | Residential | IPv4 | 82 |
Inferred from path position, not from any declaration by either party. A network appearing here is carrying these routes; whether that is a paid transit arrangement, a backup, or something else is not something routing data can tell you.
Transit
Downstream networks
Networks for which AS237 was observed as the last hop before the origin, meaning it appears to provide them transit.
| AS | Network | Type | Families | Paths seen |
|---|---|---|---|---|
| AS11206 | Ferris State University | Education | IPv4 | 1,983 |
| AS25609 | Detroit Medical Center | Unclassified | IPv4 | 1,080 |
| AS36375 | University of Michigan | Unclassified | IPv4 IPv6 | 966 |
| AS231 | Michigan State University | Unclassified | IPv4 IPv6 | 407 |
| AS400238 | PIE&G | Unclassified | IPv4 | 225 |
| AS27274 | Central Michigan University | Unclassified | IPv4 IPv6 | 220 |
| AS62618 | Michigan Technological University | Education | IPv4 | 185 |
| AS394769 | University of Michigan - Flint | Unclassified | IPv4 | 126 |
| AS22251 | Regional Educational Media Center 1 (REMC1) | Unclassified | IPv4 | 125 |
| AS62676 | University of Michigan - Dearborn | Unclassified | IPv4 | 124 |
| AS1638 | Mott Community College | Education | IPv4 | 123 |
| AS1432 | Albion College | Unclassified | IPv4 | 117 |
| AS396470 | Lansing Community College | Unclassified | IPv4 | 104 |
| AS46825 | Coldwater Board of Public Utilities | Unclassified | IPv4 IPv6 | 97 |
| AS229 | Merit Network Inc. | Unclassified | IPv4 IPv6 | 95 |
| AS22217 | Calvin College | Unclassified | IPv4 | 75 |
| AS177 | University of Michigan | Unclassified | IPv6 | 66 |
| AS402639 | Washtenaw | Unclassified | IPv4 | 63 |
| AS393817 | Lake Michigan College | Unclassified | IPv4 | 62 |
| AS46241 | Washtenaw ISD | Unclassified | IPv4 | 62 |
| AS400927 | Barger Creek Wireless | Unclassified | IPv4 | 61 |
| AS19106 | Andrews University | Unclassified | IPv4 IPv6 | 61 |
| AS15099 | County of Monroe | Unclassified | IPv4 | 57 |
| AS11494 | Kellogg Community College | Education | IPv4 | 43 |
| AS393665 | Baker College | Unclassified | IPv4 | 38 |
| AS32285 | Henry Ford College | Unclassified | IPv4 | 23 |
| AS395945 | Holland Board of Public Works | Unclassified | IPv4 | 16 |
| AS3730 | Aquinas College | Education | IPv4 | 14 |
| AS30154 | Davenport University | Unclassified | IPv4 | 14 |
| AS53263 | Grand Rapids Community College | Unclassified | IPv4 | 10 |
| AS40044 | Bronson Healthcare Group, Inc. | Unclassified | IPv4 | 6 |
Adjacency
Adjacent networks
Every AS seen directly next to AS237 in a routing path, in either direction.
| AS | Network | Type | Families | Paths seen |
|---|---|---|---|---|
| AS1299 | Arelion Sweden AB | Transit | IPv4 IPv6 | 4,454 |
| AS174 | Cogent Communications, LLC | Transit | IPv4 IPv6 | 2,294 |
| AS11206 | Ferris State University | Education | IPv4 | 1,983 |
| AS6939 | Hurricane Electric LLC | Transit | IPv4 IPv6 | 1,610 |
| AS2914 | NTT America, Inc. | Transit | IPv4 IPv6 | 1,266 |
| AS11537 | Internet2 | Unclassified | IPv4 IPv6 | 1,129 |
| AS25609 | Detroit Medical Center | Unclassified | IPv4 | 1,080 |
| AS36375 | University of Michigan | Unclassified | IPv4 IPv6 | 966 |
| AS7018 | AT&T Enterprises, LLC | Residential | IPv4 IPv6 | 487 |
| AS231 | Michigan State University | Unclassified | IPv4 IPv6 | 468 |
| AS11164 | Internet2 | Education | IPv4 IPv6 | 346 |
| AS293 | ESnet | Unclassified | IPv4 | 232 |
| AS400238 | PIE&G | Unclassified | IPv4 | 225 |
| AS27274 | Central Michigan University | Unclassified | IPv4 IPv6 | 220 |
| AS3303 | Swisscom (Schweiz) AG | Residential | IPv4 | 202 |
| AS62618 | Michigan Technological University | Education | IPv4 | 185 |
| AS394769 | University of Michigan - Flint | Unclassified | IPv4 | 126 |
| AS22251 | Regional Educational Media Center 1 (REMC1) | Unclassified | IPv4 | 125 |
| AS62676 | University of Michigan - Dearborn | Unclassified | IPv4 | 124 |
| AS1638 | Mott Community College | Education | IPv4 | 123 |
| AS1432 | Albion College | Unclassified | IPv4 | 117 |
| AS396470 | Lansing Community College | Unclassified | IPv4 | 104 |
| AS46825 | Coldwater Board of Public Utilities | Unclassified | IPv4 IPv6 | 97 |
| AS229 | Merit Network Inc. | Unclassified | IPv4 IPv6 | 95 |
| AS14907 | Wikimedia Foundation Inc. | Hosting | IPv4 IPv6 | 90 |
| AS22217 | Calvin College | Unclassified | IPv4 | 75 |
| AS177 | University of Michigan | Unclassified | IPv6 | 66 |
| AS402639 | Washtenaw | Unclassified | IPv4 | 63 |
| AS393817 | Lake Michigan College | Unclassified | IPv4 | 62 |
| AS46241 | Washtenaw ISD | Unclassified | IPv4 | 62 |
| AS400927 | Barger Creek Wireless | Unclassified | IPv4 | 61 |
| AS19106 | Andrews University | Unclassified | IPv4 IPv6 | 61 |
| AS15099 | County of Monroe | Unclassified | IPv4 | 57 |
| AS11494 | Kellogg Community College | Education | IPv4 | 43 |
| AS393665 | Baker College | Unclassified | IPv4 | 38 |
| AS32285 | Henry Ford College | Unclassified | IPv4 | 23 |
| AS395945 | Holland Board of Public Works | Unclassified | IPv4 | 16 |
| AS30154 | Davenport University | Unclassified | IPv4 | 14 |
| AS3730 | Aquinas College | Education | IPv4 | 14 |
| AS53263 | Grand Rapids Community College | Unclassified | IPv4 | 10 |
| AS40044 | Bronson Healthcare Group, Inc. | Unclassified | IPv4 | 6 |
Adjacency is not the same as peering. Being next to each other in a path covers paid transit, settlement-free peering and customer connections alike, and routing data cannot distinguish them. Treat this as "these networks exchange routes", nothing more specific.
Interconnection
Exchange presence
Internet exchanges where Packet Clearing House has a port recorded for AS237, largest fabric first. An exchange is shared switching where networks interconnect directly rather than paying a transit provider to carry traffic between them, so turning up at one is a deliberate choice about how this network wants to be reached. Each name opens that exchange's own page, with its peering LANs and every other network recorded on it. Recorded at 2 exchanges across 1 country and 1 region.
| Exchange | Location | Their address | Member ports |
|---|---|---|---|
| Equinix Internet Exchange Chicago | Chicago, United States | 208.115.136.39 | 280 |
| Detroit Internet Exchange | Detroit, United States | 209.124.52.12 | 102 |
Unlike the tables above, this is recorded rather than inferred. An address on a peering LAN is at that exchange by definition. Two carve-outs all the same. Member ports counts every participant at the exchange, not this network's ports, so read it as a size proxy. And an absent exchange means PCH has no record of it, not that the network is not there.
Provenance
Where this comes from
Derived from routing tables collected at 2026-08-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.02M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.
Cross-check against RIPEstat or BGP.tools, which observe from a different and larger set of vantage points.
Exchange presence comes from a separate dataset: the directory collected 2026-08-09 by Packet Clearing House (https://www.pch.net/ixp/data), covering 1,327 exchanges and 93,164 recorded member ports, licensed CC BY-NC-SA 3.0.
PeeringDB is the better-known directory and is deliberately not the source here: its acceptable-use policy forbids the bulk storage this needs. The two answer different questions anyway. PeeringDB reports what an operator declares about itself; this reports what PCH has recorded.